INA331 - Low-Power, Single-Supply, CMOS Instrumentation Amplifiers

Sep 18, 2026

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INA331 and INA2331 are rail-to-rail output, low-power CMOS instrumentation amplifiers designed for both single-supply and bipolar-supply operation. The family delivers low-cost, low-noise amplification of differential signals with low quiescent current and fast return to normal operation after shutdown. Key specifications include gain accuracy (G=5 with 0.02%), low offset voltage, high CMRR, low bias current, wide temperature range (-55°C to +125°C), and high bandwidth up to 2.0 MHz.

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Description

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ESD (Electrostatic Discharge) Sensitivity

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INA331 INA2331 SBOS215C – DECEMBER 2001 – REVISED APRIL 2005 Low-Power, Single-Supply, CMOS INSTRUMENTATION AMPLIFIERS FEATURES ● DESIGNED FOR LOW COST ● HIGH GAIN ACCURACY: G = 5, 0.02%, 2ppm/°C ● GAIN SET WITH EXT. RESISTORS FOR > 5V/V ● LOW OFFSET VOLTAGE: ±250µV ● HIGH CMRR: 94dB DC, 50dB at 45kHz ● LOW BIAS CURRENT: 0.5pA ● BANDWIDTH, SLEW RATE: 2.0MHz, 5V/µs ● RAIL-TO-RAIL OUTPUT SWING: (V+)– 0.02V ● WIDE TEMPERATURE RANGE: –55°C to +125°C ● LOW QUIESCENT CURRENT: 490µA max/chan ● SHUT DOWN: 0.01µA ● MSOP-8 SINGLE AND TSSOP-14 DUAL PACKAGES DESCRIPTION The INA331 and INA2331 are rail-to-rail output, low-power CMOS instrumentation amplifiers that offer wide range, singlesupply operation as well as bipolar-supply operation. The INA331 family provides low-cost, low-noise amplification of differential signals with a low quiescent current of 415µA (dropping to 0.01µA when shutdown) . Returning to normal operation within microseconds, this INA can be used for battery or multi-channel applications. Configured internally in a gain of 5V/V, the INA331 offers flexibility in higher gains by choosing external resistors. APPLICATIONS ● INDUSTRIAL SENSOR AMPLIFIERS: Bridge, RTD, Thermocouple, Position ● PHYSIOLOGICAL AMPLIFIERS: ECG, EEG, EMG ● A/D CONVERTER SIGNAL CONDITIONING ● DIFFERENTIAL LINE RECEIVERS WITH GAIN ● FIELD UTILITY METERS ● PCMCIA CARDS ● AUDIO AMPLIFIERS ● COMMUNICATION SYSTEMS ● TEST EQUIPMENT ● AUTOMOTIVE INSTRUMENTATION The INA331 rejects line noise and its harmonics, because common-mode error remains low even at higher frequencies. High bandwidth and slew rate makes the INA331 ideal for directly driving sampling Analog-to-Digital (A/D) convertersas well as general-purpose applications. With high precision, low cost, and small packages, the INA331 outperforms discrete designs. They are specified fora wide temperature range of –55°C to +125°C. V+ V– Shutdown Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. All trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2001-2005, Texas Instruments Incorporated [www.ti.com](www.ti.com) ABSOLUTE MAXIMUM RATINGS(1) Supply Voltage, V+ to V–. ................................................................... 7.5V Signal Input Terminals, Voltage(2) ..................... (V–)– 0.5V to (V+) + 0.5V Current(2) . .................................................... 10mA Output Short-Circuit(3) . ............................................................. Continuous Operating Temperature . .................................................–55°C to +125°C Storage Temperature . .....................................................–65°C to +150°C Junction Temperature . ..................................................................... 150°C Lead Temperature (soldering, 10s) . ................................................ 300°C NOTES: (1) Stresses above these ratings may cause permanent damage. Exposure to absolute maximum conditions for extended periods may degrade device reliability. (2) Input terminals are diode-clamped to the power-supply rails. Input signals that can swing more than 0.5V beyond the supply rails should be current limited to 10mA or less. (3) Short-circuit to ground, one amplifier per package. ELECTROSTATIC DISCHARGE SENSITIVITY This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.

FAQs

What are the main features of INA331/INA2331?

They provide rail-to-rail output, low-power CMOS instrumentation amplification, high gain accuracy, low offset voltage, high CMRR, low bias current, and wide operating temperature range.

How is the gain set for INA331?

INA331 is configured internally for a gain of 5 V/V, and higher gains are achieved by selecting external resistors.

What kinds of signals and systems can INA331 be used in?

It targets industrial sensor amplification (bridge, RTD, thermocouple), physiological amplifiers (ECG/EEG/EMG), A/D signal conditioning, differential line reception, test equipment, audio and communication systems, and automotive instrumentation.

Sep 18, 2026

Upload by Mimi